1- ) Yes
2- ) It’s a hidden partition visible only to TI and was designed for someone with only 1 internal HD and no external drives. My advice – don’t use it unless necessary.
3- ) It’s totally up to you and your needs. You need to read up on the difference and decide.

Regarding the differential vs. incremental strategy question, you should be aware that (at least in the Home version) there is a bug that doesn't allow to validate the last differential image created if all the previous differentials based on that same full image haven't been retained. A requirement that would lead to a buildup of repetitive recordings of the same changes and thus to a considerable waste of storage space.

As much as I agree with TheWeaz about the decision being up to your needs, that bug would, in my opinion, rule out the differential strategy. If it is present also in the Server version, of course, and not fixed yet.

1) Is there a way to verify that Acronis True Image Server backs up data that is in use. The reason being is that we always have multiple documents open and being updated as with databases (MS SQL) and I need to be certain that all data is being backed up

2) Why do you suggest not to use Acronis Secure Zone?

3) I did read up on the difference and it isn't clear enough as to what would be best. This is what I would like to achieve.

3.1) A complete backup (clone to an external media e.g DVD, external harddrive) of the entire server (first time backup)

3.2) A complete backup of files/folders, databases on a daily basis. The reason being almost all the data changes on a daily basis. I wanted to understand what difference between incremental and differential was more clearly. ​

4) Are there any drawbacks of compressing the backups e.g. corruption, etc

1) I wouldn't know how to verify that, but I always do my imaging from Windows with all 36 processes running in background, AV Guard and firewall included. Never had a problem. Still, some users routinely boot from the Rescue CD (running under Linux OS) for imaging, just to be double-sure. But that approach wouldn't work for you, since it would be interrupting the normal work of the system in Windows.

2) You might want to manage your image files (eg. copy a particular one to keep it), something you can't do if they are stored inside SZ.

3) You will get a better picture if you study the User's Guide, but as far as I understand your situation, I think the incremental strategy would be the most appropriate for daily imaging (without too many incrementals!). It may be a good idea to ask Acronis about the differentials validation bug I mentioned before (or just carry out a simple test).

Cloning is a one-time operation meant to migrate to a larger drive. It's not to be confused with imaging/restoring.

4) Imaging under Normal compression (the default) is standard with TI users and it's also the best time/size compromise. I never heard of any case of image corruption to be blamed to compression.

Please keep in mind that I'm talking out of Home version experience only.